title: [The production of mouse model of slowly progressive diabetes mellitus and the preventive effect of low molecular weight chitosan on the progression of the diabetes mellitus].
abstract: The aim of our study was to produce a new diabetic model by a single i.p. injection of various doses of streptozotocin (STZ) to 8-week-old male Institute of Cancer Research (ICR) mice. When STZ was i.p. injected at doses rainging from 75 to 200 mg/kg, in the group injected 200 mg/kg STZ, the non-fasting serum glucose levels markedly rose from 1 week after STZ administration and the high glucose levels were maintained for 9 weeks. The serum glucose levels in the group administered 100 mg/kg STZ were within a normal range at 1 week after STZ administration, but thereafter continued to increase gradually till 9 weeks. In contrast with the serum glucose levels, a marked reduction in the percentage of the relative numbers of β-cells in the islets of pancreas from 1 week in mice injected 200 mg/kg STZ was observed. On the other hand, in 100 mg/kg STZ mice, the number of β-cells was almost normal percentage at 1 week and then continued to gradually decrease as the time went on throughout 24-week-observation. These results indicate that only the 100 mg/kg STZ injection produces slowly progressive diabetes mellitus in mice. Low molecular weight (LMW) chitosan (chitosan lactate, average of molecular weight: 20000) was administered as drinking water from prediabetic stage (from 2 weeks after 100 mg/kg STZ injection). The 0.2% or 0.8% LMW chitosan administration prevented the progression of 100 mg/kg STZ-induced slowly progressive diabetes mellitus. The mechanisms, which LMW chitosan is effective in this model may be discussed on β-cells.
authors.affiliation: Laboratory of Analytical Pharmacology, Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan. mitoh@meijo-u.ac.jp
authors.forename: Mikio
authors.initials: M
authors.lastname: Ito
mesh_terms: D000818:Animals; D048271:Chitosan / Q000627:therapeutic use*; D003921:Diabetes Mellitus, Experimental / Q000517:prevention & control*; D004195:Disease Models, Animal; D018450:Disease Progression; D008297:Male; D051379:Mice; D008970:Molecular Weight; D013311:Streptozocin
chemical_list: D013311:Streptozocin; D048271:Chitosan